AEM Dryflow Filters - An Air Filter Is an Air Filter, Right? Not Anymore

AEM's New Dryflow Filter Element

We don't expect that you lie awake at night over this, but when you think about performance air filters, two types typically come to mind. The first and most common is a cotton-gauze type, which has layered cotton-gauze sandwiched between screen mesh and uses an oil that wicks into the material to help trap dirt as air passes through it. The second familiar offering is an oiled foam type.

Both types deliver good filtration capabilities but have always had drawbacks: The main one being concerns of over-oiling after the filter is cleaned. This could result in that extra oil traveling up the intake path and damaging the little expensive sensors along the way, which can void your warranty.

While doing R&D on its Brute Force Intake systems, AEM discovered a reusable filtering media that does not require oil, is easy to clean, and filters just as well as anything else out there. Named Dryflow, it is also lighter and more durable than a typical cotton-gauze because it does not use mesh to form the filter pleats.

Because you never oil this filter, servicing time is reduced from as much as a day for cotton gauze to a couple of hours for the Dryflow. The Dryflow Synthetic filter media is hydrophobic, which is a fancy term for saying it resists water absorption, so it dries fast, and since you never have to oil it (and wait for the oil to wick to the cotton), once it's dry, it is ready to use again.

Starting at filtration, the part that matters most to your motor, AEM used Southwest Research Institute (SWRI) in San Antonio, Texas, for independent testing of its new material. SWRI performs various testing for OEMs and aftermarket companies. The company used SWRI for testing only, and despite the results of the tests, SWRI does not endorse any type of filter media, which is hy the company is "independent."

Following the industry standard Air Cleaner Test for internal combustion engines, SWRI conducted a fine-dust test. AEM's Dryflow Synthetic air filter had an initial filtration efficiency of 98.4 percent and a cumulative efficiency of 99.4 percent down to 1 micron of particulate. For you off-road fanatics, think of the silt you run through and you will realize why trapping that small amount of particle is important.

AEM also asked SWRI to run a coarse-dust test using the same procedures, which is another common type of test. It started and ended at 99.4 percent filtration efficiency, which means in street conditions, nothing but clean air is getting past this material. If you want to check out the test results for yourself, AEM posted them on its website.

When AEM received its dirty filters back from SWRI, the technicians cleaned them and sent them back for a retest. With a cotton-gauze element, every time you wash them, some of the material can wash away with it, so the more you clean it, the less filtration efficiency it will have. Think of it like this: When you wash your favorite T-shirt, what comes out of the lint basket? The same principle applies here. The results of these tests showed virtually no degradation over a new Dryflow element, netting 98.5 percent initial and 99.4 percent cumulative efficiency again.

AEM's Dryflow Synthetic filters are only available from AEM. They are included in the company's Brute Force Intake kits and are sold separately as universal or replacement filters, so if you have one of AEM's old intakes, you can replace the filter with a Dryflow. By the time you read this, a cross-reference chart for easy reference should be on AEM's website.

Yeah, They Are Crazy Over There at AEM"OK, it didn't degrade after one cleaning," you say, "but what about after multiple cleanings?" AEM wondered the same thing, so the company performed a "severe abuse" test (their words) to see how it would hold up in the worst possible circumstances. This began with applying used motor oil to the element and cleaning it with AEM's solution. After two cleaning cycles, it wasn't coming out, so AEM tried brake cleaner, carburetor cleaner, bleach, and finally, industrial parts solvent. When AEM had extracted as much oil as it could, the company dried it with 125 psi of air pressure from a 1/8 nozzle, a big no-no with cotton gauze. Then, they sent the filter back to SWRI, where it still filtered at 98.2 percent initial and 97.1 percent cumulative efficiency. This was also done with one of AEM's previous cotton-gauze elements, too, but didn't bother to send it for testing because you could see straight through the mesh after cleaning. We shouldn't have to say this, but AEM does not recommend repeating this test. Instead, check out the results on AEM's website.